用双螺杆挤出机脱硫制备再生胶的工艺及性能

利用改进的双螺杆挤出机对废旧轮胎橡胶胶粉进行剪切脱硫,讨论了螺杆转速和反应温度对脱硫效果及再生胶力学性能的影响,通过扫描电镜分析了胶粉脱硫前后形貌的变化及再生胶硫化试样的界面结合状况。结果表明,废旧轮胎橡胶胶粉的凝胶含量和交联密度随着螺杆转速和反应温度的升高明显下降,脱硫胶粉恢复了塑性,再生胶硫化试样的界面结合紧密。将螺杆转速控制在50～120 r/min、反应温度控制在190/180/170～210/190/200℃时脱硫效果最佳,此时再生胶的拉伸强度由未脱硫前的3.1 MPa提高到了12.4 MPa,扯断伸长率由75%提高到452%。     

螺杆组合对用废旧轮胎胶粉制备再生胶工艺的影响

介绍了自行研制的螺杆组合结构,考察了不同螺杆组合对废旧轮胎胶粉制备再生胶工艺的影响。结果表明,螺杆组合对于用废旧轮胎胶粉脱硫制备的再生胶力学性能的影响很大。相对于主喂比( 喂料螺杆与主螺杆转速之比) 而言,螺杆的转速和温度对废旧轮胎胶粉的脱硫效果及再生胶力学性能的影响程度较高。在采用螺杆组合Ⅱ制备再生胶时,若将螺杆转速设为100 r /min、主喂比设为1. 4、温度设为190 ℃( Ⅰ区) /180 ℃ ( Ⅱ区) /160 ℃ ( Ⅲ区) ,则废旧轮胎胶粉的凝胶质量分数由脱硫前的86. 32%降至77. 56%,交联密度由14. 86 × 10 － 5 mol /cm3 降至5. 38 × 10 － 5 mol /cm3 ; 此时获得的再生胶的力学性能最好,拉伸强度达到14. 4 MPa,扯断伸长率约为446%。     

双螺杆挤出改性胶粉/天然橡胶并用胶的性能研究

采用双螺杆挤出改性胶粉,研究挤出转速对挤出改性胶粉/天然橡胶（NR）并用胶性能的影响。结果表明：采用双螺杆挤出,在强剪切力作用下,硫化胶粉的（硫化胶）交联网络结构破坏,随着挤出转速的增大,硫化胶粉的交联密度先迅速下降后趋于稳定;挤出改性胶粉与NR并用形成的“海-岛”结构随着硫化胶粉交联网络结构打开程度的增大逐渐消失,挤出改性胶粉与NR形成了共交联网络结构;硫化胶粉交联网络破坏程度适宜时,挤出改性胶粉易与NR在硫化过程中形成交联网络,并避免硫化胶粉过度降解,从而使得并用胶获得较大的拉伸强度和拉断伸长率。     

废旧子午线轮胎胶粉的再生研究

采用自制再生剂对废旧子午线轮胎胶粉进行再生研究,分析胶粉粒径、再生剂用量和软化剂用量对再生效果的影响。结果表明:随着废旧子午线轮胎胶粉粒径的增大,再生胶的邵尔A型硬度变化不大,拉伸强度和拉断伸长率减小;随着再生剂用量的增大,再生胶的门尼粘度减小,拉伸强度和拉断伸长率呈先增大后减小的趋势;随着软化剂用量的增大,再生胶的拉伸强度和拉断伸长率呈先增大后减小的趋势。当胶粉粒径为0.45mm、胶粉用量为100份、再生剂用量为7份、软化剂用量为3份时再生效果较好。再生胶用量对NR混炼胶物理性能影响较大。     

密炼机工艺对废胎胶粉脱硫效果的影响

研究了密炼机再生工艺对废旧轮胎胶粉再生效果的影响。对再生橡胶的交联密度、溶胶含量、门尼黏度、物理机械性能和动态力学性能进行了分析。结果表明,溶胶含量随着脱硫温度的升高而逐渐增大;交联密度随着脱硫温度的升高而逐渐降低;根据horikx理论分析表明高混脱硫再生工艺再生过程中化学键的断裂以交联键断裂为主。再生胶的焦烧时间(ts 1)和再硫化时间(t9 0)随着脱硫温度的升高均呈现逐渐增大的趋势,拉伸强度随脱硫温度的增加逐渐降低。随脱硫时间的增加,再生胶硫化胶的拉伸强度略有降低,拉断伸长率变化不大。     

双螺杆挤出机转速比对胶粉及其天然橡胶并用胶性能的影响

用双螺杆挤出机对硫化胶粉进行机械力化学改性,得到改性胶粉(MWRP),将其与天然橡胶(NR)并用,研究了挤出机转速比对MWRP自由基浓度、交联密度以及MWRP/NR并用胶力学性能、微观形貌的影响。结果表明,随着转速比的降低,剪切作用增强,胶粉体系的交联网络结构得到破坏,体系自由基浓度呈现先上升后降低的趋势,胶粉的交联密度降低; MWRP/NR并用胶的力学性能得到改善,在转速比为3.5时,拉伸强度和扯断伸长率达到最大,分别为19.7 MPa和607%; 并用胶拉伸断面的缺陷减少,胶粉颗粒与橡胶基体的相容性得到改善。     

采用微波脱硫罐制备三元乙丙橡胶再生胶

采用自制微波脱硫罐对三元乙丙橡胶(EPDM)胶粉进行微波脱硫制备EPDM再生胶,并研究搅拌速度和脱硫温度等对EPDM再生胶性能的影响。结果表明:搅拌速度对EPDM胶粉的脱硫均匀性有影响,但对EPDM再生胶的物理性能影响不大;脱硫温度对EPDM胶粉的脱硫效果影响很大;当脱硫功率为2 k W、胶粉填充量为5 kg、搅拌速率为60r·min-1、脱硫温度为270℃左右时,EPDM再生胶物理性能较佳。     

废旧轮胎胶粉应力诱导脱硫反应影响因素的研究

在废旧轮胎胶粉/EPDM的熔融挤出过程中,以仲丁醇为脱硫反应促进剂,研究螺杆转速和挤出反应温度对脱硫共混物凝胶质量分数(w)、凝胶分子链结构以及SBR/脱硫共混物再硫化材料物理性能的影响。结果表明:在废旧轮胎胶粉/EPDM的熔融挤出过程中,随着螺杆转速和挤出反应温度的升高,废旧轮胎胶粉颗粒所受的机械剪切应力作用增强,引起废旧轮胎胶粉中交联网络的断裂、降解或解交联反应,导致脱硫共混物w显著减小以及SBR/脱硫共混物再硫化材料中凝胶粒子尺寸明显减小;添加仲丁醇有利于脱硫反应的进行,并具有抑制交联副反应和保护脱硫产物中双键的作用,使脱硫共混物的w进一步减小;在螺杆转速为1 000 r.min-1、挤出反应温度为240℃的条件下,SBR/脱硫共混物(添加仲丁醇)再硫化材料的拉伸强度和拉断伸长率分别为19.3 MPa和567%。     

轮胎胶脱硫共混物增韧聚丙烯的影响因素

在轮胎胶粉与热塑性弹性体(POE)共混物的熔融挤出过程中添加有机醇类化合物作为脱硫反应促进剂,研究双螺杆挤出机的螺杆转速和挤出反应温度对轮胎胶脱硫共混物的凝胶含量、溶胶分子链结构及增韧PP材料力学性能的影响.实验结果表明:随着双螺杆挤出机螺杆转速的增加或挤出反应温度的升高,轮胎胶粉颗粒所受到的机械剪切应力作用或热能作用均明显增强,强烈的剪切应力和热能可引发轮胎胶中交联网络的断裂、降解或解交联反应发生,引起脱硫共混物中凝胶含量明显下降、凝胶粒子尺寸明显减小以及与PP材料相容性明显改善.添加有机醇-1化合物作为脱硫反应促进剂时,有利于脱硫反应的进行,有利于脱硫产物中双键的保护,并引起脱硫共混物凝胶合量进一步下降、凝胶颗粒尺寸进一步减小和增韧PP材料力学性能进一步提高.在240℃条件下添加有机醇-1化舍物进行脱硫反应,当脱硫反应螺杆转速由400 r/min增加至1200 r/min时,所得脱硫共混物增韧PP材料(PP/DGTR/POE=70/24/6)的缺口冲击强度可由17.4kJ/m2提高至34.4 kJ/m2,并且引起此共混材料拉伸强度、断裂伸长率、弯曲模量及熔体指数的明显增大.     

转矩流变仪制备再生胶的工艺及性能

利用转矩流变仪的高温剪切作用并添加再生活化剂420对废旧轮胎胶粉(GTRP)进行了再生,讨论了活化剂用量和加工温度对再生胶再生程度及力学性能的影响。结果表明,随着活化剂用量的增大和温度的上升,GTRP溶胶含量明显上升,门尼粘度和交联密度均明显下降。转子转速为50r/min,加工时间为15min,加工温度为170℃,活化剂420用量为0.5份时,所得再生胶具有最佳综合力学性能。     

单螺杆挤出机连续脱硫制备再生胶的结构与性能

利用本课题组研制的单螺杆挤出机,对废旧轮胎胶(GTR)粉进行连续脱硫制备再生胶(DGTR),并对DGTR进行再硫化制成DGTR硫化试样.结果显示,随螺杆转速增加,DGTR凝胶含量和DGTR硫化试样交联密度逐渐降低,DGTR硫化试样的拉伸强度和拉断伸长率有所提高;螺杆转速设定为40 r·min^-1时,在205℃脱硫温度下取得了最好的脱硫效果,DGTR硫化试样的拉伸强度和拉断伸长率分别约为11 MPa和386%.从红外光谱和光电子能谱的分析结果推测,在单螺杆挤出机的剪切和热等的共同作用下,GTR粉中部分S-S键和C-S键发生了断裂.     

Effects of shear stress and subcritical water on devulcanization of styrene–butadiene rubber based ground tire rubber in a twin‐screw extruder

The devulcanization reaction of styrene–butadiene rubber (SBR) based ground tire rubber (GTR) in GTR/ethylene–propylene–diene monomer rubber (EPDM) blend was investigated through a compound‐induced reaction by increasing screw rotation speed and being in the presence of subcritical water. The effects of temperature, pressure, screw rotation speed, or promoting agents on the gel content, Mooney viscosity, and Fourier transform infrared spectra of the sol of the devulcanized blends (devulcanized ground tire rubber (DGTR)/EPDM) were measured, and the mechanical properties and microstructures of the revulcanized blend ((DGTR/EPDM)/SBR) were characterized. The results show that subcritical water as a swelling agent and reaction medium promotes the devulcanization reaction, increases the selectivity of the crosslink breakage, keeps the extrusion material from oxidative degradation, reduces the gel particle size of the devulcanized blends, and significantly improves the mechanical properties of the revulcanized SBR/(DGTR/EPDM) blends. In subcritical water, the suitable promoting agents (alkylphenol polysulfide 450, hydrogen peroxide H₂O₂, or 450/H₂O₂) accelerate the devulcanization reaction, keep the double bond content, and lead to further decrease of the gel content and Mooney viscosity of the devulcanized blends and further increase of the mechanical properties of the revulcanized SBR/(DGTR/EPDM) blends. Especially the compound promoting agent (450/H₂O₂) improves the selectivity of the crosslink breakage in devulcanization of SBR‐based GTR. When 450/H₂O₂ is added as a compound promoting agent at the best reaction condition in subcritical water (200°C, 1.6 MPa and 1000 rpm), the tensile strength and elongation at break of the revulcanized SBR/(DGTR/EPDM) blends reach to 85.4% and 201% of vulcanized SBR (24.0 MPa, 356%), respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1845–1854, 2013     

轮胎胶应力诱导脱硫化及PE-HD动态交联热塑性弹性体制备

采用在废旧轮胎胶粉(GTR)与高密度聚乙烯(PE-HD)的熔融挤出过程中提高双螺杆挤出机螺杆转速的高剪切应力诱导方法,研究了双螺杆挤出机的螺杆转速、挤出反应温度及脱硫促进剂仲丁醇、烷基酚多硫化物(420或450)和正丁胺对轮胎胶脱硫共混物的凝胶含量、熔体流动速率、溶胶红外吸收光谱及轮胎胶脱硫共混物/三元乙丙橡胶(EPDM)动态交联热塑性弹性体力学性能的影响。结果表明:高转速同向双螺杆挤出机的高剪切作用可诱发废旧轮胎胶共混物中交联网络的断链和解交联反应,引起脱硫共混物凝胶含量的下降、未熔融凝胶颗粒尺寸的减小及熔体流动速率的增加;4种促进剂均具有明显促进脱硫反应的作用,其中450或正丁胺的促进脱硫效果较好,并引起脱硫共混物凝胶含量下降、熔体流动速率上升及动态交联热塑性弹性体力学性能的明显改善;当以正丁胺为脱硫促进剂时,最佳脱硫反应条件(240℃和1000r/min)下,脱硫共混物/EPDM动态交联热塑性弹性体的拉伸强度和断裂伸长率分别达到12.5MPa和440.6%。     

Devulcanization of waste tires using a twin‐screw extruder: The effects of processing conditions

During recent decades, for both economic and environmental reasons, recycling of waste tires that are based on SBR/NR has been widely considered. In this study the devulcanization process of the tread section of waste tires was carried out by using a twin‐screw extruder. The effects of barrel temperature and screw speed were investigated. Percent of devulcanization, sol fraction, and curing behavior of devulcanized samples were studied. After the addition of curing agents into the devulcanizates, the general behavior of the rheometry test for rubber compounds was observed. Percent of devulcanization and sol fraction depended on the screw speed and barrel temperature, respectively. The devulcanized samples were formulated with virgin rubber (15/85 wt% ratio) and re‐cured successfully. Tensile strength, elongation at break, compression set, hardness, and resilience were evaluated. It was found that the mechanical properties of the compound containing devulcanizates were slightly inferior to those of the virgin compound. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

亚临界流体挤出法复合诱导SBR基轮胎胶脱硫化及 再硫化材料力学性能

在SBR基轮胎胶(GTR)与三元乙丙橡胶（EPDM）混合物的熔融挤出过程中,采用改变亚临界流体品种和提高螺杆转速的方法,研究了亚临界流体（水,乙醇,丙醇）、螺杆转速、烷基酚多硫化物促进剂（450）以及温度对脱硫共混物（DGTR/EPDM）凝胶含量、门尼粘度、溶胶红外光谱及脱硫共混物共混丁苯橡胶（SBR）再硫化材料（SBR/(DGTR/EPDM)）力学性能的影响,对再硫化材料的试样断面形貌也进行了SEM观察。实验结果表明：亚临界流体（水,乙醇,丙醇）作为一种溶胀剂和反应性介质能够很好地促进脱硫反应,提高交联键断裂的选择性,降低脱硫产物的凝胶含量和凝胶颗粒尺寸并明显提高脱硫共混物共混丁苯橡胶再硫化材料的力学性能,其中亚临界乙醇的作用最显著。当450作为一种脱硫促进剂,在最优亚临界乙醇挤出反应条件（200℃,1.6 MPa,600 rpm）下,脱硫共混物共混丁苯橡胶分别达到丁苯生胶混炼硫化材料拉伸强度（24.0MPa）和断裂伸长率（356%）的99.6%和209%。     

废旧轮胎橡胶的常温粉碎及性能研究

采用盘式磨设备对废旧轮胎胎面胶颗粒进行常温粉碎,研究胶粉性能及其对丁苯橡胶(SBR)硫化胶物理性能的影响,并与胎面胶颗粒进行对比。结果表明:常温粉碎胶粉的粒径比胎面胶颗粒降低了一个数量级,形状更加不规则且表面粗糙;动盘和定盘相对转速对常温粉碎胶粉粒径及其分布影响不大,但动盘和定盘间隙影响较大;常温粉碎胶粉的热稳定性比胎面胶颗粒低,且交联密度减小一半以上;与胎面胶颗粒相比,添加常温粉碎胶粉的SBR硫化胶的拉断伸长率有很大提高,但邵尔A型硬度、100%和300%定伸应力以及拉伸强度有所减小。     

Continuous ultrasonic devulcanization of unfilled butyl rubber

The devulcanization of resin‐cured unfilled butyl rubber with a grooved‐barrel ultrasonic reactor under various processing conditions was carried out. The experiments indicated that, because of the lower unsaturation and good thermal stability of butyl rubber, its devulcanization could be successfully accomplished only under severe ultrasonic‐treatment conditions. Gel permeation chromatography measurements were carried out for the virgin gum and sol part of devulcanized samples to study the changes in the rubber network during the devulcanization process. The obtained data showed a significant molecular weight reduction and a broadening of the molecular weight distribution upon devulcanization, which indicated that the devulcanization and degradation of butyl rubber occurred simultaneously. The rheological properties showed that devulcanized butyl rubber was more elastic than the virgin gum. The vulcanizates of the devulcanized butyl rubber showed mechanical properties comparable to those of the virgin vulcanizate. The thermal behaviors of the virgin and devulcanized butyl rubber were different and were correlated to the double‐bond content. The structural characteristics of the devulcanized butyl rubber were simulated with the Dobson–Gordon theory of rubber network statistics. A fairly good agreement between the experimental data and theoretical prediction was achieved. The simulation of devulcanized butyl rubber indicated that the rate of crosslink rupture was much higher than that of the main chain. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1316–1325, 2004     

脱硫胶粉改性沥青的研究

研究了不同用量的脱硫胶粉和未脱硫胶粉对橡胶沥青粘度、常规性能、贮存稳定性及显微结构的影响。结果表明：脱硫胶粉改性沥青的粘度和软化点与未脱硫胶粉的相比有明显下降,但针入度和贮存稳定性均增加。虽然对生产工艺有利．但不利于提高橡胶沥青的高温性能。脱硫胶粉改性沥青的剪切变稀行为减弱。脱硫胶粉改性沥青的显微图表明：胶粉颗粒发生了破坏,并有炭黑游离出来。     

Properties of natural rubber vulcanizates containing mechanochemically devulcanized ground tire rubber

The devulcanization of ground tire rubber (GTR) was carried out with a self-designed pan-mill type mechanochemical reactor. Gel fraction and crosslink density measurements confirmed the occurrence of stress induced mechanochemical devulcanization of GTR. The partially devulcanized GTR (dGTR) was blended with virgin natural rubber (NR) at different ratios. The curing characteristics and mechanical properties of these composites were investigated and compared with those composites of raw ground tire rubber (rGTR) and NR. The results showed that the tensile properties of the dGTR/NR vulcanizates were much better than those of the rGTR/NR vulcanizates, which are comparable to or even better than the virgin vulcanizate, indicating the significant benefit of mechanochemical devulcanization. At the GTR content of 10%, the tensile strength of the dGTR/NR blends increased to 23.2 MPa from 13.7 MPa of the rGTR/NR blends, enhanced by 69% through partial devulcanization of GTR, and the elongation at break increased by 47%.